Thermionic-tube construction



Mar. 3, 192,5. 1,528,735

F. s. MCCULLOUGH.

THERMIONIC TUBE cousmucnon Filed June 2, 1924 W/ZW Patented Mar. 3, 1925.

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I Application filed June 2,

. which the following is a specification.

This invention is for a thermionic tube construction wherein one or more. coils are enclosed within the walls of the tube, as outlined in my co-pending application Serial No. 308,978, filed July 7, 1919, and which will be issued as a patent on June 3, 1924.

In my said application, it is proposed to include coils of a thermionic tube circuit within the envelope of the tube, whereby a number of external lead connections may be eliminated and a material advantage result in the shortening of lead wires and the consequent reduction of, distortion due to the decreased impedance and capacity of such leads. Such a construction, furthermore, enables apparatus involving the use of thermionic tubes to. be very compact byreason of the saving of space gained by the elimination of such coils and lead wires.

The present invention has for its object to; provide a novel supporting means for colls within a tube.

A further object of the invention is to provide a novel transformer construction within a thermionic tube.

These and other objects and advantages are obtained byv my invention, which may be understood by reference to the accompanying drawings, in which:

1g. 1 is a' somewhat diaelevation of a device embo ying my invention;

Fig. 2 is a side view thereof;

Fig. 3 is a section in the plane of line III-III of Fig. 2;

Fig. 4 is a wiring diagram illustrating a circuit embodying tubes otmy invention Fig. 5 is a diagrammatic view of wiring of one type of tube embodying the invention; i

Fig. 6 is a front view of a slightly modified form; and

Fig. 7 is a 'view showing a, different circuit connection embodying myinvention.

In the drawings, 5 designates'the usual glass stem of a thermionic tube construction which is flanged at 6, the flange being seammatic front 1924. Serial No, 717,232.

cured to the envelope 7 (shown in dotted lines) after all the parts have been assembled in accordance with the usual practice.

Carried by the stem are two spaced apart rigidsupports ,8 which carry the plate 9 of the tube. The upper ends of the posts 8 project above the top of the plate a c'onslderable distance, passing through opposite ends of a heat resistant insulating cylinder or body 10, which is thus rigidly supported above the plate. v Carried on or supported by this cyllnder are one or more coils for use in the thermionic tube circuit. 1 have shown two such coils, 11 and 12, the former being included in the plate circuit of the tube as the primary of a radio-frequency transformer, while the latter, designated 12, constltutes the secondary winding of the transformer. The remaining portion of the tube may follow any standard or preferred construction. I have shown a filament or hot cathode 13 carried by supports 14 and 15 in the stem. The grid 16 is carried by supports 17 and 18, also fused into the stem. The three electrodes may connect with the usual connector plugs atthe base of the tube.

In Figs. 1 and 5, 19 designates the two filament connections, 20 is the grid connection, and 21 is the plate terminal.

In the form illustrated, the coil 11 is in series with the plate, while coil 12 has'one terminal connected in the filament circuit inside the-tube, its other end passing through the glass envelope of the tube, as indicated at 22, the projecting wire 23 beingadapted for connection with other parts of the circuit. I haye shown it, in Fig. 4, as leading to the grid of similar tube.

In Fig. 4, which illustrates a circuit possible with my invention, two tubes A and B are coupled together for eifecting radio fre quency amplifications in a radio-receiving system. Various other circuits and COIlIlGCtlOIlSIOII the coils may be devised for utilizing the- 'PIll'lClPlES of'my invention, and will readily suggest themselves. to those familiar with thermionic or electron valve circuits.

In Fig. 6, I have shown a slight modifi;

cation wherein the stem 25 has supports 26 which carry the plate 27. Within the plate are the usual filament 28 and grid 29. Carried on the plate supports is a heat resistantcylinder or tube 30 that surrounds the elec-.

trades, on which are carried one or more coils, s uch as 31 and 32, which may be'connected in the circuit as hereinbefore I described,- or in any other suitable fashion. One 0011, for instance, might be included in the grid circuit of the tube and the other in the plate circuit, to, efiect regeneration.-

velope having an anode, a cathode and a grid therein, a coil supporting member inside the vessel, inductively coupled coils on the upporting member, one of said coils being connected inside the tuberwith one of the electrodes.

3. An electron tube comprising an envelop 'having an anode, a cathode and a grid thgiein, a coil supporting member inside the ve l, inductively coupled coils on the supporting member, one of said coils being in series with the anode of the tube.

. LA thermionic tube comprising an envelope, a stem within the envelope, three electrodes comprising a grid, a plate, and a cathode, respectively, inside the tube, supporting means inside the: tube for the grid and cathode, supporting means in the tube for. the plate, a heat resistant insulating body carried by the plate, supportin means in spacedrelation thereto, a pair 0 inductively coupled coils carried by the body,- each coil having an internal connection with one, of the electrodes.

In testimony whereof I hereunto aflix my signature.

FREDERICK s. .McOULLOUGH. 

